I overwintered some lettuce, and so can you. Below freezing temperatures usually mean the end of the growing season for most things, but certainly not for everything. The truth is that salad greens (lettuce, spinach, kale, etc.) can be overwintered, especially if you grow them under a cold frame or hoop house or in an otherwise protected location. Some can even be harvested throughout the winter if the conditions are right.
Last fall I had nine lettuce seedlings that I had started indoors. I transplanted them outside in either late October or early November (memory isn’t serving me right now). I placed some straw mulch around them, and then covered them with a makeshift cold frame made out of PVC pipe and floating row cover. There they remained all winter long.
I live in Boise, Idaho. The winters here are relatively mild (compared to the rest of Idaho), but we still have plenty of days with below freezing temperatures. Our frost-free growing season is about 160 days long. The average low temperature from December through February is around 25° F. This past winter, our lowest temperature (according to Weather Underground) was -7° F, and we had at least 30 days in which the low temperature reached 20° F or lower. Needless to say, it was a chilly winter.
But my lettuces held on…at least most of them. When I uncovered my cold frame in early March, I found that six of my nine lettuce seedlings had survived. It didn’t surprise me that a few had perished – some of the seedlings that I had transplanted were quite small, and I had serious doubts that they would make it. I was satisfied to see that the majority of them were still alive. Two-thirds ain’t all that bad.
The varieties that I planted were “Freckles” and “Winter Density.” I chose these because the descriptions I read gave me the impression that they were ideal for overwintering. But descriptions be damned. I suggest seeing for yourself. Take any variety of lettuce or other salad green and experiment in your own garden. See what you can get to overwinter with or without protection. Seeds are fairly inexpensive, and it is worth seeing what you can get to survive through the winter. Differing climates – both macro and micro – will produce varied results, and every year things will be a little different. This is one of the many joys of gardening. Weather and climate will always be factors, but they can also be markers to help us see what we can get away with. And if one of the things you get away with is getting lettuce to survive a harsh winter, it means you will be eating garden fresh lettuce long before your neighbor.